In many patients who suffer from disfunction of the mitral and/of tricuspid valve(s) of the heart, surgical repair of the valve (i.e. "valvuloplasty") is a desirable alternative to valve replacement. One specific group of patients who are typically candidates for such surgery are children who suffer from congenital atrioventricular septal defect (AVSD).
Remodelling of the valve annulus (i.e. "annuloplasty") is central to many reconstructive valvuloplasty procedures. Such remodelling of the valve annulus may be accomplished by implantation of a prosthetic ring (i.e. "annuloplasty ring") to stabilize the annulus and to correct or prevent valvular insufficiency which may result from defect or disfunction of the valve annulus.
The prior art has included numerous annuloplasty rings, such as those described in U.S. Pat. Nos. 4,042,979 (Angell); 4,290,151 (Massana); 4,898,446 (Reed); 4,602,911 (Ahmadi et al.); 5,061,277 (Carpentier et al.); and 5,201,880 (Wright et al.), as well as International Patent Publication WO 91/17721 and Foreign Patent Publication SU197710.
One problem associated with the annuloplasty rings of the prior art is that, when such annuloplasty rings are implanted into children (such as pediatric patients with AVSD) the subsequent growth of the patient may render the annuloplasty ring too small for its intended function. Thus, follow-up surgery my be necessary to replace the originally implanted annuloplasty ring with a larger ring suitable for the then-current size of the patient.
Although some of the annuloplasty rings of the prior art have incorporated means for adjusting the size of the ring at the time of implantation, applicant is aware of no prior art annuloplasty ring which is constructed and equipped for post-implantation size adjustment, in situ, to accommodate changes in annular size due to growth of the patient.